By [1]}, the symplectic resolution \(\pi \)  is semismall. Rapagnetta, in the proof of [2]}, shows that the singular locus \(\Sigma \subset M\)  is isomorphic to \((J^\vee \times J)/ \pm 1\) . In particular, \(\Sigma \)  has finite quotient singularities, which implies that the intersection complex \({IC}_{\Sigma }\)  is the constant sheaf. The result then follows from the Decomposition Theorem for semismall morphisms (see Theorem 4.2.7 in the survey [3]}).

